Cranial Cruciate Ligament Injuries in Dogs: What You Need to Know

When we think of cruciate ligament tears, it’s usually in association with pro athletes or weekend warriors — but our dogs can suffer cranial cruciate ligament (CCL) injuries as well. In fact, it’s the most common orthopedic problem that we veterinarians see.

Remember that old song Dry Bones, about how “the shin bone's connected to the knee bone”? Well, the cranial cruciate ligament is one of the ligaments that connects the thighbone to the shinbone where they meet at the knee (known as the stifle joint in dogs) and helps hold the joint stable. Basically, it functions like a rope, preventing the stifle bones from shifting abnormally during activity.

What Causes CCL Disease

When the CCL becomes injured — which can happen suddenly or over a long period — it’s not only painful in the instant it happens, it also leads to painful degenerative joint disease if it’s not repaired. Dogs typically suffer CCL tears (also known as CCL disease) for three major reasons:

They are overweight.

They are out of condition and then are asked to perform athletic feats that are beyond their abilities (weekend warrior syndrome).

They jump, twist, turn or land wrong (on slippery surfaces, for instance).

Dogs are also more prone to CCL tears if they’ve had a previous CCL injury on the opposite leg. A body slam during rough play can leave a dog sitting on the sidelines howling. And CCL tears can result from long-term chronic degeneration. We don’t know yet if there is a genetic component to CCL ruptures. Any breed or mix can suffer one, but this type of injury is most often seen in young Labrador Retrievers and Rottweilers (less than 4 years old), dogs older than 5 years, and young large-breed dogs. Other breeds that seem to have a disproportionate number of CCL injuries include Bernese Mountain Dogs, Mastiffs, German Shepherd Dogs, Golden Retrievers and Saint Bernards. Spayed females are also susceptible to these injuries.

Signs of CCL Rupture

You may or may not see the actual injury occur. If you do, the first sign will likely be a loud yelp of pain from your dog.

The most obvious clue that your dog may have suffered a CCL injury is lameness or reluctance to put weight on a rear leg. Your dog may hold his limb up or use the leg intermittently. Some dogs display what we call a lazy sit, holding the affected leg out to the side. You may notice that the stifle joint is swollen or that it makes a clicking sound when your dog walks, which may indicate meniscal injury. In many instances, the injury may have been building up for some time. A CCL tear, or rupture, can be partial or complete.

Any time your dog appears to be lame, he needs to be seen by a veterinarian. To diagnose the problem and rule out other causes of lameness, your veterinarian may manipulate the leg to check the stifle’s range of motion, remove fluid from the stifle joint (a procedure known as arthrocentesis) to check for the presence of inflammatory cells, microorganisms or immune-mediated diseases that could be causing the problem, and examine the knee joint arthroscopically to get a look at the ligaments and cartilage. Radiographs (x-rays) or an MRI can also help to confirm a diagnosis.